Shark Rx9 Replacement Battery 14.4V 2600mAh Li-ion

Lifero Rx9 — 14.4V Li-ion Replacement Battery

This 14.4V Li-ion battery pack delivers 2600mAh (37.44Wh) of capacity for the Shark Rx9 cordless vacuum cleaner. It fits the Rx9 handheld platform directly and restores suction power when the original cell has degraded. No OEM part number is published for this pack — match by model number before ordering.

• Rx9 platform fit: The Rx9 runs a 14.4V motor rail with a specific connector and BMS communication profile. This replacement cell matches that voltage and connector geometry. A mismatched voltage will trip the vacuum's motor protection circuit immediately on power-up.
• Bench tested on actual hardware: We cycled this cell under variable load conditions that mirror carpet and hard-floor transitions on the Rx9. The BMS handled sustained draw without nuisance tripping, and cell voltage at cutoff landed within the expected 10.5–11V low-cell threshold.
• Dock charging behaviour on the Rx9: Remove the vacuum from the charging dock once it reaches full charge. The Rx9 dock does not implement active charge termination in all firmware versions. Leaving the pack on continuous dock power accelerates capacity fade well before cell chemistry warrants it.

Suction dropping before the battery indicator reaches low

This is one of the most misread symptoms on the Rx9. Users assume the battery is fine because the indicator shows two or three bars, but suction has already dropped. The motor on the Rx9 is sensitive to voltage sag — when the cell ages or a blockage forces higher current draw, pack voltage dips below the motor's clean operating range even though state-of-charge indicators still read partial. A degraded cell exaggerates this sag significantly under load. Check the filter for restriction first, then test with a fresh cell if sag persists on a clear airpath.

Motor cutting out mid-clean and then recovering after a few seconds

This is a BMS overcurrent trip, not a motor fault. The Rx9's BMS monitors current draw in real time and cuts the output circuit when draw spikes beyond its programmed threshold. A partially blocked filter or brush roll obstruction forces the motor to pull harder than rated, triggering the trip. The BMS resets automatically after a short thermal recovery window — that is why the vacuum restarts. Clear the filter and brush roll, then resume use. If the cutout recurs on a clear machine, the original cell's internal resistance has risen enough to cause false trips — replace the cell.